As known to persons skilled in the art, the state of the art comprises a plurality of models of automotive harvesters, and each one of these models presents different technical-constructive characteristics that are especially suited to the most varied harvest needs.
In the case of sugar cane harvesters, and drawing reference to FIGS. 1 and 2, they are typically arranged to gather sugar cane plants planted in SC lines and comprise a knockdown bar 15 or a top cutter, row dividers 14, one or more knockdown rollers 16, base cutting disks 111, at least a raising roller 17, a set of conveyance rollers 12 and chopping rollers 13, which cut the stalk of the sugar cane into more or less uniform billets having an approximate length of 200 to 300 mm. The residues that are gathered jointly with the cane are separated by way of an extractor 18 and the billets SCT are dispensed for transport, such as a transshipment dumper (not shown).
The elements that make up a sugar cane harvester, as well as the workings thereof, such as illustrated in FIGS. 1 and 2, are well known by persons skilled in the art.
It is also widely known by persons skilled in the art that automotive harvesters, such as, for example, sugar cane harvesters, are liable to clogging, that is, the build-up of vegetable crop and other waste, such as earth, stones etc. at the mouth of the machine or along the conveyance rollers or even in the chopping rollers, hampering the adequate flow of the material gathered. In this regard, it is worth emphasizing that clogging may occur due to different factors, such as, for example, the erroneous setting of the harvest parameters (such as too high or too low a speed) or due to the characteristics of the vegetable crop itself, as well as soil and climate.
In any case, it is known that during harvesting, a sugar cane harvester may sustain clogging due to the unexpected amount of cane, waste, or other elements, obliging the operator to stop the machine and clean it, causing wastage of work hours and thus compromising productivity.
Bearing in mind this scenario, the state of the art discloses some attempts to prevent or mitigate the clogging of automotive harvesters.
Document U.S. Pat. No. 3,470,681 describes, for example, a control system applicable in automotive harvesters that includes a variable speed unit connected to the conveyance system. This variable speed unit enables the control of the speed of the elements comprised within the conveyance system in accordance with the characteristics of the vegetable crop and, especially, in accordance with the thickness of the vegetable crop, which can be measured in accordance with the spacing between the floating rollers in said conveyance system.
Document U.S. Pat. No. 3,609,947 describes, for example, an automotive harvester whose conveyance system comprises an electric switch liable to activation based on the volume of vegetable matter gathered. Once activated (likely due to clogging), said electric switch activates solenoids, and this activation triggers the reduction of the automotive speed of the harvester and increases the speed of harvest treating assembly.
Document U.S. Pat. No. 6,315,658 describes, for example, an automotive harvester which, in order to maintain a substantially constant crop flow to the crop processing assembly, notwithstanding a variation in the crop amount (likely clogging), comprises a control circuit capable of controlling the propulsion speed of the harvester and/or the speed of the components within the conveyance system. This control is based on crop flow data obtained by a sensor that detects the speed and/or crop amount, and by a fill sensor associated with a buffer which temporarily accumulates the crop at the location upstream from the crop processing arrangement.
Although the state of the art comprises methods of operating automotive harvesters which, in one way or another, are designed to prevent or mitigate clogging or else keep the harvester working constantly, it is obvious that said methods foresee means of control (alteration of the propulsion speed of the harvester itself and/or alteration of the speed of the cutting module elements) only based on parameters directly or indirectly measured by the components comprised therein.
This limitation is highly negative. After all, such measurement is carried out at just one point of the harvester, and may result in diagnoses such as “false positive” (incorrect positioning of the floating rollers owing to various problems, without the occurrence of clogging) or “false negative” (correct positioning of the floating rollers, with the occurrence of clogging at other points of the machine).